Treatment of waste water containing microorganisms has been performed for a fairly long period of time. However, treatment processes based on electrolysis have hitherto not been completely problem-free. Inefficient processes as well as expensive equipment or high energy consumption have previously prevented improved handling of microorganisms occurring in e.g. waste water, cooling water, ballast water, and recirculated washing water. U.S. Pat. No. 5,419,824 discloses an electrolytic cell for destroying contaminants. However, this process is very expensive and inefficient for applications where large volumes of water are treated due to extensive pressure drop, low flow rates, and low current efficiency.
In WO 02/26635, it has been further tried out embodiments for reducing contaminants and microorganisms in which alternating current is supplied to a cell. This has, however, not always been seen to be a successful way of performing the chemical reactions in the cell.
It has been further seen in the prior art that cleaning systems involving reduction of contaminants often have been provided with a reactor tank arranged to the pipings through which the medium to be cleaned passes. This configuration, however, often results in pressure drops and lower throughput of the medium to be cleaned. The retention time may also be prolonged which is not always satisfying, particularly if large volumes of contaminated water needs rapid treatment.
The present invention intends to provide an efficient process and a cell solving the problems of the prior art. A further object of the present invention is to provide an improved control of the hydrogen and chlorine formation in the electrolytic cell.